What are the long-term impacts of early childhood education? A study by SESP associate professor Diane Schanzenbach and her co-researchers found that children in higher-quality kindergarten classrooms were still reaping benefits 25 years later.

Specifically, they earn more and are more likely to attend college, be married, own a home and have retirement savings. There is a strong correlation between kindergarten achievement test scores and adult outcomes.

“These findings are exciting for a number of reasons,” Schanzenbach says. “Early life investments pay off over a child's lifetime; individual teachers have a documentable lifetime impact on their students; and skills other than narrowly defined math and reading standardized test scores are really important in determining later life outcomes, so perhaps emphasizing them so strongly — to the detriment of other skills — under No Child Left Behind is misguided.”

The study investigated the long-term impacts of kindergarten classrooms by drawing on experimental data from Project STAR, where 11,571 students in Tennessee and their teachers were randomly assigned to kindergarten classrooms. The researchers correlated that data with the students’ tax returns at age 27.

For the purposes of Schanzenbach’s study, kindergarten quality was defined as smaller class size, more experienced teachers and higher classmate test scores. When the researchers looked at each component, students in smaller classes are significantly more likely to attend college. Students with a more experienced kindergarten teacher have higher earnings, an average of $1,093 more a year at age 27. Students in classrooms where the students achieve more have higher earnings, college attendance rates and other outcomes. While the effects of class quality on test scores in later grades fade out, noncognitive gains persist.

“We find that the most likely mechanism for these improvements is an improvement in social, behavioral and emotional skills imparted by high-quality teachers in a good classroom environment,” Schanzenbach says.

The Quarterly Journal of Economics published her study with colleagues Raj Chetty, John Friedman, Nathaniel Hilger and Danny Yagan, all of Harvard University, and Emmanual Saez of University of California-Berkeley.

The impacts of education have traditionally been measured by achievement on standardized tests. This study shows that the classroom environments that raise test scores also improve long-term outcomes. Although students who were randomly assigned to higher-quality classrooms in grades K–3 have better adult outcomes, the same students do not do much better on standardized tests in later grades.

“These results suggest that policy makers may wish to rethink the objective of raising test scores and evaluating interventions via long-term test score gains. Researchers who had examined only the impacts of STAR on test scores would have incorrectly concluded that early childhood education does not have long-lasting impacts,” the researchers say. They conclude that while the quality of education is best judged by adult outcomes, end of-year test scores are a reasonably good short-term measure of the quality of a classroom.